HOVER INFRARED SUPPRESSION SYSTEMS (HIRSS) were developed to reduce the infrared (IR) signature of helicopter engines. These systems have been employed to reduce the infrared emissions of the exhaust from engines employed in helicopter applications, such as the General Electric T-700 engine employed in every helicopter designs such as for example, the Black Hawk UH-60, the Apache AH-64 and the AH-1, among others, in use by the U.S. Military. The HIRSS systems have been successful in reducing the IR signature without the benefit of high emissivity coatings (Hi-E), but IR emissions have not been completely eliminated. Because the “threat systems” (heat seeking missile technology, for example) is constantly improving, and because engine temperatures are constantly increasing, resulting in higher exhaust temperatures, it is necessary to further improve the IR signature of such engines to neutralize these threats.
Infrared suppression systems such as the HIRSS are known and have been in use for some time. U.S. Pat. No. 6,253,540 to Chew et al. assigned to the assignee of the present invention, discloses an apparatus for suppressing infrared radiation emitted from the aft end of a gas turbine engine. The system features a mechanical arrangement of baffles connected together to mix hot and cool gas flow together to affect the line-of-sight infrared radiation signature of the exhaust. Additional improvements have been made to these HIRSS. While these improvements have been effective in suppressing infrared radiation, the continued improvement in engine operating temperature as well as improvements in detection by advances in threat systems have made engines operating even with improved HIRSS systems increasingly vulnerable. What is need is HIRSS system that suppresses infrared radiation emitted by engines used in helicopter technology such as the GE T-700 engines